Single-use disposable packages are often manufactured from flexible packaging material which, by suitable processing, folding and sealing, is formed into packages of the desired configuration. The packages are often provided with some form of opening arrangement, for example a region of the material weakened by perforation, this region being, on the outside of the package, connected to a gripping device in the form of a plastic pull-ring or the like, with the aid of which the package may thus be opened.
Packages of the above-mentioned type are also employed for the packaging of previously sterilized contents, for example UHT treated long-life milk. In such cases, the packaging material must be sterilized prior to being brought into contact with the contents. To sterilize the packaging material the packaging material, while it is still in the web or sheet form to is brought into contact with a liquiform chemical sterilization agent which, after having been in contact with the packaging material for the requisite time to obtain the desired level of bacterial extermination, is once again removed from the material. Application of the sterilization agent to the packaging material may be effected, for instance, by passing the packaging material web through a bath of sterilization agent, or by vaporizing the sterilization agent directly onto the web. Since the surplus sterilization agent is, after the requisite contact time, removed from the material web by means of, for example, squeezer rollers or hot air knives, it is of the utmost importance that the material web does not display creases or other irregularities, for example folded regions or pre-applied details, since these would, on the one hand entrain an undesirably large volume of sterilization agent, and, would also render impossible the thorough removal of the sterilization agent after the treatment time. For this reason, it has not hitherto been possible to fit such pre-applied details as gripping devices or the like to packaging material which is, by forming and/or sterilization processes, to be converted into individual packages of the above-mentioned type.
Hence, it is generally desirable within this art to develope a method of applying a gripping device to an aseptic package which is sterilized by the application of a liquiform sterilization agent to the packaging material prior to being formed into a finished package.